Pitchers, who are in the most responsible charge of a baseball game, practice various techniques to vary the speed and direction of travel of a baseball. Presently, however, the speed of a pitched ball is merely measured at a specific position with a speedgun. The measurement of degree that a baseball falls, or curves to the left or the right side, depends on the naked eyes of the observer or the final stopping point of the baseball. Accordingly, there is a drawback to present baseball detection devices in that the curving degree and the velocity variation of a pitched ball between a pitcher and a home base are not exactly detected.
It is an object of the present invention to provide a method for detecting the motion variation of a baseball, wherein the method can detect a curving degree and the velocity variation of a pitched baseball, in order to solve the above-problems. To solve the problems, a plurality of sensors are situated at right angles to an imaginary straight line between a pitcher and a catcher. Each of the sensors detects the momentary passing positions of a pitched baseball in the form of a two-dimensional coordinate, and the time that a baseball passes through the sensors.
It is another object of the present invention to provide a device for detecting the motion variation of a baseball, which can detect the curving degree and the velocity variation of a pitched ball.